Spring-applied brake



SSP- 24 B. DICK SPRING-APPLIED BRAKE Filed May 20, 1339 MK Tm ND E vm N`la U B l v WIW M m m 5 ..,....1.., 4 L U n Patented Sept. 24, 1940l lUNITED STATES PATENT ol-FICE Burns Dick, Ferg son, Mo., assignor toWagner Electric Corporation, St. Louis, Mo., a corporation of DelawareApplication May zo, 1939, serial No. 274,691 14 claims. (c1. 18s-17o) Myinvention relates to brakes and more parof and the other end pivotallyconnected to the ticularly to a brake in which the friction element l'end of shoe 4 by means of a pin I8. The innerl thereof isspring-applied. end of the piston rod has mounted thereon a One of theobjects of my invention is to produce piston yI9 positioned in `thecylinder and held A an improved brake which is applied by a spring onthe rod by means of a nut 20. This piston 5 and released by fluidpressure. forms with the cylinder and the end wall thereof,

Another object of my invention is to so ema fluid receiving chamber 2|which issealed by body the applying spring in a brake of the type a cup22 Cooperating with the piston and a cup referred to thatthe spring maybe easily com- 23 cooperating with the` end wall of the cylinder pressedand mounted in operative position during and the piston rod. The pistonrod, externally 10 assembly of .the brake. of the cylinder, is providedwith a lateral exten- Still another object of my invention is to so sion24 projecting through asuitable enlarged associate the brake applyingspring with the opening 25 to the exterior of the backing plate brakereleasing iiuid motor that the resulting n as best shown in Figure 3.Fluid is adapted toA construction will be such that it can beeasily beforced into chamber 2| by way of I a longi- 15 incorporated in a brakeassembly which has been tudinal passage 26 in the piston rod and acomdesigned to be normally released and applied municating cross passage21 in the projection byauid motor. 24. A conduit 28 connected to theprojection Other objects of my invention will become applaces thepassage 2l in communication with a parent from the following descriptiontaken in suitable source of pressure such as a master cylin- 20connection with the accompanying drawing in der (not shown). In order tobleed the chamwhich Figure 1 is a side view of a brake, showber, thepiston rod I'I is also provided with a ing my invention embodiedltherein; Figure 2 is longitudinal passage 29 in communication with alongitudinal cross-sectional view of the fluid chamber 2| and connectingthis passage with motor` and associated brake applying spring; and theatmosphere is a passage 30 closed by a screw- 5 Figure 3 is across-sectional view taken on the plug 3|. The enlarged opening25vthrough which line 3 3 of Figure projection 24 extends is closed by awasher 32 Referring to the drawing in detail, numeral held against thesurface of the backing plate by I indicates a drum iixed to a rotatablemember means of a spring 33.

30 such as a shaft, and numeral 2, a backing plate In order that thebrake shoes may be applied 30 or support secured to some xed member asis to the drum, there is provided a strong coil common practice. Withinthe drum are two spring 34 which is mounted in surrounding relabrakeshoes 3 and 4 mounted upon adjustable tion to cylinder 9 and the sleevesI 0 and II with anchor pins 5 and 6 carried by the backing plate, itsends in abutting relation with the hexagonal 35 The shoes carry theusual friction lining 1 and 8. flanges I4 and I 5. The spring is at alltimes 35 In accordance with my invention, I employ a under compression,thus expanding the ends of cylinder 9 provided vwith external threadslfor the shoes against the drum through the medium cooperation with aninternally threaded sleeve of the connecting member I2 and the pistonrod I8. Upon cylinder 9 is slidablymounted a sec- I'I. The shoes areheld in a central position ond sleeve II which is prevented fromrelative when they are disengaged from the drum' by a 40 rotation withrespect to the cylinder by cooperleaf spring 35 one end of which isbolted to the ating fiat surfaces between the sleeve and the backingplate by a bracket 36 and the other end cylinder. The sleeve I0 issecured to an att-achof which extends into -a notch 31 in a downwardlying member I2 for connecting it tothe end of extending portion 38 of thepiston rod.

shoe 3 by a pin I3. This attaching member is The operation of the abovedescribed brake is 45 provided with a hexagonalshaped ange I4 believedto be obvious. The shoes will be held whereby sleeve I0 may be screwedon oroff the in engagement 'with the drum by the strong cylinder 9 by asuitable wrench. The sleeve II spring 34. When it is desired to releasethe is also formed with a hexagonal-shaped flange shoes, iluid underpressure is forced into chamber I5 for receiving a suitable wrench tohold the 2|, thereby compressing the spring and moving 50 cylinder fromturning when sleeverI is screwed the shoes to their retracted positionswhere they on for oi the cylinder. are out of engagement with the drum.

The flange portion I5 of sleeve II abuts a flange The construction just-described is such as to I6 on a piston rod II which has one' end'extendpermit easy installation of the strong spring 34 ing into thecylinder through the end wall therewhen the brake is assembled. Thevspring, when 55 in its uncompressed conditio is first mounted uponcylinder 9 with oneend against the hexagonal flange of the sleeve ll.Next, sleeve l@ is inserted in the other end of the spring and screwedon the cylinder. Duringv this screwing operation piston i9 will be inabutting relation with the closed end of the cylinder. To protect thecup 22, a washer 3S is secured on the piston rod ahead of the cup. ,Thescrewing operation may be easily performed by suitable wrenchescooperating with the hexagonal flanges l@ and of sleeves l0 and il. Whenthe spring is corn-7 pressed the proper amount, the attaching member l2is connected to shoe 3 and then liuid under pressure is forced intochamber 2i to thereby move the piston and cylinder in oppositedirections and to such an extent that the spring will' be so compressedthat the shoes can be placed in the drum. The construction is compactand very little space is employed to mount the spring in the assemblysince it' surrounds the cylinder of the fluid motor. Also, thearrangement is such. .that the spring and uid motor assembly can besubstituted for the usual fluid motor ina brake assembly which has beendesigned to be normally released and applied only by a fluid motor. To

accomplish this substitution, all that is necessary is to cut off aportion of the toe of each shoe and then attach member I2 to shoe 3 andthe piston rod l1 to shoe 4.

The brake has been found to be Very useful in the control of cranes andhoists where it is desired to have the brake shoes normally held appliedand released only during short intervals,

Being aware of the possibility of modifications in the particularstructure herein described without departing from the fundamentalprinciples of my invention, I do not intend that its scope be limitedexcept as set forth by the appended claims. l

Having fully described my invention, what I claim as new and desire tosecure by Letters Patent of the United States isz' 1. In brakingapparatus, a rotatable drum, a. friction element for cooperation withthe drum. and having adjacent ends, a coil spring interposed between theends of the friction element for actuating said ends into engagementwith the drum, said spring having its axis positioned at right angles toa radius of the drum, abutments operatively connected to the ends of thefriction elementand engaged by the ends of the spring, and

means positioned within the coils of the spring for moving saidabutments toward each other to compress the spring.

2. In braking apparatus, a rotatable drum, a friction element forcooperation with the drum, a coil spring for actuating the frictionelement into' engagement with the drum, vand a fluid motor positionedwithin the coils of the spring for compressing the spring and causingthe friction element to be disengaged from the drum.

3. In braking apparatus, a support, a rotatable drum, a friction elementfor cooperation With the drum and having adjacent ends, spaced abutmentsassociated with the ends of the friction element, a coil springinterposed between said abutments for forcing the ends ofthe frictionelement into engagement with the drum, floating means for moving saidabutments toward each other to compress the spring and cause thefriction element to be disengaged from the drum, and yieldable means formaintaining the floating means and the ends of the friction element frommoving relative to the support when said friction element is disengaged.

4. In braking apparatus, a rotatable drum, a

friction element for cooperation with the drum, a- `coil spring foractuating the friction element into engagement with the drum, a oatingfluid motor positioned within the coils of the spring for compressingthe spring and causing the friction element to be disengaged from thedrum, and yieldable -means for preventing the ends of the frictionelement and the fluid motor from shifting with respect to the supportwhen the friction element is disengaged from the drum.

5. In braking apparatus, a support, a rotatable drum, a friction elementfor cooperation with the drum, a coil spring for actuating the frictionelement into engagement with the drum, a fluid motor positioned withinthe coils of the spring for compressing the spring and causing thefriction. element to be disengaged from the drum, and a leaf springsecured to the support and cooperat ing with an element of the fluidmotor for yieldably holding the fluid motor from movement with. respectto the support when the friction element is disengaged from the drum.

6. In braking apparatus, a rotatable drum, a friction element forcooperation with the drum and having adjacent ends, a cylinder connectedto one end of the friction element, a piston connected to the other endof the frictionv element, means forming a fluid chamber between thepiston and cylinder whereby uid under presn sure therein will cause thecylinder and piston to move in such opposed directions as to move theends of the friction element away' from the drum, and a coil springsurrounding the cylinder for forcing the ends of the friction elementinto engagement with the drum.

'l'. In braking apparatus, a rotatable drum, a friction element forcooperation with the drum and having adjacent ends, a cylinder connectedto one end of the friction element, a 'piston rod connected to the otherend of the friction element and extnding into the cylinder, a pistonsecured to he rod and positioned in the cylinder, means including thepiston and the cylinder for forming a fluid pressure chamber between thepiston and the end of the cylinder through which the piston rod extends,spaced abutments carried by the cylinder and piston rod, and a coil'spring surrounding the cylinder and compressed between the abutments.

8, In braking apparatus, a rotatable drum, a friction element forcooperation with the drum and having adjacent ends, a cylinder connectedto one end of the friction element, a piston rod connected to the otherend of the friction ele-- ment and extending into the cylinder, a pistonsecured to the rodand positioned in the cylinder, means including thepiston and the cylinder for forming a fluid pressure chamber between thepiston and the end of the cylinder through which the piston rod extends,spaced abutments carried by the cylinderand piston rod, a coil springsurrounding the cylinder and compressed between the abutments, and meansfor adjusting one of said abutments relatively to the member on which itis carried.

9. In braking apparatus, a support, a rotatable drum, a friction elementfor cooperation with the drum and having adjacent ends, a cylinderconnected to one end of the friction element, a piston in the cylinderand connected to the other end of the friction element, means forming afluid chamber between the piston and cylinder whereby fluid underpressure therein will cause the cylinder and piston to move in suchopposed directions as to move the ends of the friction element away fromthe drum, a coil spring surrounding the cylinder for forcing the ends ofthe friction element into engagement with the drum, and a leaf springsecured to the support and cooperating with the cylinder and pistonassembly for yieldably holding said assembly from movement with respectto the support when the friction element'is disengaged from the drum.

10. In braking apparatus, a rotatable drum, a friction element forcooperation with the drum and having adjacent ends, an externallythreaded cylinder, means for connecting said cylinder to one end of thefriction element and comprising an internally threaded sleevecooperating i with the cylinder, a piston rod connected to the other endof the friction element and extending into the cylinder, a pistonconnected to the pis- Will be moved away from the drum, ment associatedwith the threaded sleeve, a second abutment associated with the pistonrod, and a coil spring surrounding the cylinder and interposed betweensaid abutments.

11. In braking apparatus, a rotatable drum, a friction element forcooperation with the drum and having adjacent ends, an externallythreaded cylinder, means for connecting said cylinder to one end of thefriction element and compris- 4 chamber to a source of 'device providedwith adjacent 12. In braking apparatus, a rotatable drum, a frictionelement for cooperation with the drum and having adjacent ends, acylinder connected to one end of the friction element, a piston rodconnected to the other end of the friction element and extending intothe cylinder, a piston secured to the rod and positioned in thecylinder, means including the piston and the cylinder for forming aiiuid pressure chamber between the piston and the end of the cylinderthrough which the piston rod extends, means providing passages in saidpiston rod for connecting the pressure and for bleeding abutmentscarried by the cylinder and piston rod, and a coil spring surroundingthe cylinder and compressed between the abutments.

13. In braking apparatus having a friction expansible ends, a unitarycontrol device for interposition beprismg spaced abutments, one abutmentwith one end of the friction device and the other abutment with theother end of the friction device, a coil spring positioned between-theabutments, and means comprising a uid motor positioned within the coilsof the spring for moving the abutments toward each other to compressthespring and cause the ends of the friction device to be disengagedfrom the drum.

ing both said abutments toward each other to compress the spring andcause the friction device to be disengaged from the drum, said meanscomprising a, uid motor having two movable elements and a fluid pressurereceiving chamber therebetween, means for connecting one of the elementsto one abutment, and means for connecting the other abutment to theother elements, said connections being such that when uid under pressuregreater vthan atmospheric pressure is received in the chamber theelements will be moved apart and the abutments moved toward each otherto compress the spring.

BURNS DICK.

